From: nze christian (christian_nze@hotmail.com)
Date: 12/03/02-10:12:25 AM Z
Sure Ken,
I can't compare a X00000$ scanning system with X00$. The filter are not of
the same quality. And what could be apply on one wiil not really work on the
other as the system is no good ebough.
A friend of mine use the Espon 2450 and make 8 pass to get a scan and The
result are really interestng and good compare to the 1 pass scan.
Amicalement
Nzé Christian
mailto:christian_nze@hotmail.com
http://www.c-nze.com
Next exhibition at Atelier Ph7 - Brussel
October -November 2002
>From: Ken Watson <watsok@frii.com>
>Reply-To: alt-photo-process-l@sask.usask.ca
>To: alt-photo-process-l@sask.usask.ca
>Subject: Scanning filtering
>Date: Tue, 03 Dec 2002 06:45:01 -0700
>
>Nze,
>
>This is also, I am sure you know, not the way most scanners work today.
>They
>are scanning all three colors at the same time. With the filters on the
>chip
>there is limited materials they can use for these filters as they need to
>withstand several semiconductor processing steps. If one is using separated
>color filters, off chip, you have an opportunity to select much better
>filtering materials and as you say only get R,G of B because that is all
>the
>light there is.
>
>There is software that can eliminate the sparkles. It just needs to be
>determined what the largest contrast step is allowable or always assume any
>large step in intensity in a black field is noise. This is generally a
>workable assumption, unless you are trying to image lint on a dark cloth.
>Ken
>l Message -----
>From: "nze christian" <christian_nze@hotmail.com>
>To: <alt-photo-process-l@skyway.usask.ca>
>Sent: Monday, December 02, 2002 2:55 PM
>Subject: Re: Scanning for greater dynamic range
>
>
> > Ken,
> >
> > I used to work with multiple scan when I made confocal microscopy. The
> > system is about the same as in astronmy but the pmt are a little
>different.
> > But the software I woprk with,(made by Leica) use an average system to
>avoid
> > noise. even with 2 scan it can give a better result. Sure the fact is it
> > work best for low value, to avoid noise in the black.
> >
> > In microscoopy I used to scan first the blue then the green and last the
> > red. each with a pmt only sensitive to this color with filters to
>avoid
> > the avoer color to pass.
> >
> > Amicalement
> >
> > Nzé Christian
> > mailto:christian_nze@hotmail.com
> > http://www.c-nze.com
> >
> >
> >
> >
> >
> > >
> > >
> > >----- Original Message -----
> > >From: "nze christian" <christian_nze@hotmail.com>
> > >To: <alt-photo-process-l@skyway.usask.ca>
> > >Sent: Monday, December 02, 2002 12:20 PM
> > >Subject: Re: Scanning for greater dynamic range
> > >
> > >
> > > > Hi,
> > > >
> > > > The double scan result in a better , because the 2 scans will be
> > >different;
> > > > the noise will not happen on the same point. The sofware will do an
> > >average
> > > > which mean that when the scan give the same result for a point, the
> > >software
> > > > let them like they are but when it give different result it will
>make
> > >the
> > > > average of the to point. this method is used in microscopy ofr
>astronomy
> > > > where single pmt are used. They often average to 8 or 16 which mean
>that
> > > > they scan 8 16 to avoid noise. a point should always give the same
> > >result
> > > > on the 8 scan, if not it apply a function or delete the point
> > >considered
> > >as
> > > > pure noise.
> > > >
> > > > In our case the noise just come from the receptor, as there is no
>change
> > >in
> > > > the light and in the photo. so this way to work avoid to many
>machine
> > >noise.
> > > >
> > > >
> > > > <If you double scan you still have the same signal to noise ratio,
> > > > <therefore
> > > > <no increase in dynamic range because you are just summing together
>to
> > > > <scans
> > > > <with the same signal to noise ratio. Unless you have software that
>can
> > > > <detect noise and remove it one is just fooling self. As far as I
>know
> > > > <this does not exist.
> > > >
> > > > Amicalement
> > > >
> > > > Nzé Christian
> > > > mailto:christian_nze@hotmail.com
> > > > http://www.c-nze.com
> > > >
> > > >
> > > > > >
> > > >
> > > >
> > > > _________________________________________________________________
> > > > MSN Messenger : discutez en direct avec vos amis !
> > > > http://www.msn.fr/msger/default.asp
> > > >
> > > >
> >
> >
> > _________________________________________________________________
> > MSN Search, le moteur de recherche qui pense comme vous !
> > http://search.msn.fr/worldwide.asp
> >
_________________________________________________________________
MSN Search, le moteur de recherche qui pense comme vous !
http://search.msn.fr/worldwide.asp
This archive was generated by hypermail 2.1.5 : 01/31/03-09:31:25 AM Z CST